Feeding on protists and particulates by the leptocephali of the worm eels Myrophis spp. (Teleostei: Anguilliformes: Ophichthidae), and the potential energy contribution of large aloricate protozoa

Abstract

The food sources of the leptocephali of the teleostean superorderElopomorpha have been controversial, yet observations on the leptocephaliof the worm eels, Myrophis spp. (family Ophichthidae) collectedin the northern Gulf of Mexico indicate active, not passive, feeding.Leptocephali had protists in their alimentary canals. Estimates ofthe physiological energetics of worm eels indicate that large aloricateprotozoa including ciliates could provide substantial energy to theseleptocephali toward the end of the premetamorphic and metamorphicstages, given the low energy requirements of metamorphosing leptocephali.Global ocean warming will likely force a shift in oceanic food webs;a shift away from large protozoa toward smaller protists is possible.Such a disruption of the oceanic food webs could further compromisethe survival of leptocephali.